James Holmes calls himself “the Joker;” not cooperating with Aurora police

Authorities have identified James Holmes, 24, as the alleged gunman responsible for killing at least 12 people and injuring dozens during a mass shooting inside a crowded movie theater in Aurora, Colorado, early Friday morning.

Law enforcement sources told CNN Holmes identified himself as "the Joker" to police and had colored his hair red.

According to NBC News' Pete Williams, he was not cooperating with authorities.

The Aurora theater was packed with people watching the premiere of the Batman movie “The Dark Knight Rises." Aurora police told CNN that the gunman shot 71 people in the movie theater.

The Associated Press is now reporting that Holmes bought a ticket to the midnight showing of the latest Batman movie and entered the theater as part of the crowd.

Authorities took Holmes into custody in a parking lot behind the theater, according to the Washington Post.

More from GlobalPost: Aurora shooting suspect in custody

The Post states that investigators believe the shooter — armed with a shotgun, rifle and two handguns — was wearing a gas mask and set off a gas canister before opening fire in the theater. The victims of the mass shooting range in age from 3 months to 45 years, reported CNN.

Police said that the apartment of the suspect was booby trapped so they evacuated five of the surrounding buildings, according to the Associated Press. Aurora Police Chief Dan Oates said bomb technicians were working on disarming some flammable or explosive material.

FBI agents reportedly used a hook and ladder fire truck and a 12-foot pole with a camera at the end to peek into the apartment, and Oates said the pictures were fairly disturbing.

The apartment was around four miles from the theater where the shooting took place.

Holmes was born December 13, 1987, according to CBS News.

President Obama, who earlier expressed his condolences to the families of the victims, said in an address Friday that "such violence, such evil is senseless," CNN reports.

A San Diego woman identified herself to ABC News as the mother of James Holmes. She said she had not yet been contacted by authorities and had been unaware of the shootings.

"You have the right person," she said. "I need to call the police… I need to fly out to Colorado."

According to a spokeswoman for the University of Colorado School of Medicine in Denver, Holmes was a student there until last month, when he withdrew without giving a reason.

Aurora, Colorado, is 17 miles from Littleton, Colorado, known for being the site of the Columbine High School massacre in April 1999.

Republican presidential candidate Mitt Romney also expressed condolences to the victims.

GlobalPost spoke with a witness, Sharon Segura, who described a brutally chaotic scene. She and her husband, Quentin Caldwell, were in the theater next to the one where the shooting occurred. 

“We get about 10 minutes into the movie and there is this big action scene and there’s lots of gunfire. And there is just maybe five or six really loud pops," Segura said. “So I freak out and I jump a little. And my husband laughs at me, and I said, ‘no you don’t understand that wasn’t part of the movie, that was real. That was way too loud.’”

Read more from GlobalPost: Eyewitness accounts: Batman premiere shooting

A man by the name of James Holmes from Aurora, Colorado, has a page on the Colorado Tea Party Patriots site. GlobalPost has not been able to confirm if this is the same man.

See GlobalPost's complete coverage of the Aurora shooting